BIRMINGHAM, Ala. (AP) - The nation’s largest regional passenger airline told pilots to avoid landing on the runway where a UPS cargo jet crashed in Birmingham because an internal review following the accident concluded planes come “dangerously close” to nearby hills if even a few feet too low.

The Atlanta-based ExpressJet Airlines, in a company alert obtained by The Associated Press, said its pilots should use the primary runway at Birmingham-Shuttlesworth International Airport when possible rather than the shorter Runway 18, where a UPS A300 jet struck trees before slamming into a hill short of the runway in August. The two pilots died, but no one on the ground was hurt.

The National Transportation Safety Board has yet to determine the probable cause of the UPS accident, and a hearing last month focused on pilot fatigue as the cause of the crash, not any possible problems with the runway. An aviation safety expert said the runway is “absolutely” safe.

But the ExpressJet report, based on both an analysis of the UPS crash and ExpressJet landings in Birmingham, said a nonstandard flight path to the runway combined the “significant threat of terrain” meant its pilots should always land on Birmingham’s main runway if it is available.

Dated about one month after the UPS crash, the ExpressJet review said the study was meant to illustrate the “tight constraints” of Runway 18, “not to instill fear” in pilots.

ExpressJet spokeswoman Samantha Harrison declined comment on the safety analysis. The company operates 14 flights daily through Birmingham as Delta or United Express, airport records show.

A spokeswoman for the Birmingham airport, Toni Herrera-Bast, wouldn’t answer questions about the ExpressJet report, including whether the authority that oversees the airport is considering any changes to the runway.

Birmingham’s main, 12,000-foot-long runway was temporarily closed for repairs the morning of the crash, and the pilot of the UPS jet decided to land on Runway 18, which is 7,000 feet long and has less guidance equipment than the longer runway.

The airplane’s path took it across several large hills at the northern end of the runway. Apparently unaware how close the aircraft was to the ground, the pilot flew into the tops of tall trees beside two homes before dawn on an overcast, drizzly morning. After impact, the aircraft plunged into the side of a hill more than a half-mile from the end of the runway, scattering wreckage across a wide area.

ExpressJet’s safety department reviewed both the UPS crash and 11 landings made by its own pilots last year on Runway 18, the analysis shows. While none of the ExpressJet flights crashed, the study found that two ExpressJet planes that were only a few feet below an ideal flight path came within 65 feet of a hilltop.

“Due to the significant threat of terrain on approach to runway 18 and the non-standard glide-path angle, all landings should be made to runway 6/24, if available,” the study concludes. “Flying ‘low’ or ‘slightly low’ … puts the aircraft dangerously close to terrain.”

Veteran airline pilot-turned-safety consultant John Cox, who grew up in Birmingham and learned to fly on Runway 18, said the runway “absolutely” is safe.

“How many hundreds and thousands of people have landed using that approach?” said Cox.

But, he said, the ExpressJet analysis highlights the difficulty pilots face when landing on Runway 18 and other runways with difficult approaches over hills or buildings. The Birmingham runway is also tricky during takeoffs because of surrounding hills, Cox said.

“It’s an appropriate step for the company to say to the crews, ‘This runway has some issues with it. If you can, use the other one,’” said Cox, who flew for commercial carriers and now is chief executive of the Washington-based Safety Operating Systems, a consulting company.

The co-pilot, Shanda Fanning, was making only her second flight to the Birmingham airport.

ExpressJet, a subsidiary of SkyWest Inc., calls itself the world’s largest regional airline with more than 2,100 flights daily on average. It operates as American Eagle, Delta Connection and United Express.